Drum-carried terminal wiper



April 1o, 195e R W, PERSONS 2,741,683

DRUM-CARRIED TERMINAL WIPER Filed May 19, 1953 .Fira .l

ffl-.9.

IN VEN TOR.

53 00./ OQEQTM PEQSoA/s,

r raQA/Eys.

United States Patent O DRUM-CARRIED TERMINAL WIPER Robert W. Persons, Claremont, Calif. (Application May 19, 1953, Serial No. 356,004

3 Claims. (Cl. 20G-166) AThis invention has to do generally with terminal or contact wipers and is more particularly concerned with wipers particularly well adapted to the wiping of contacts of such mechanisms as tuners or chanel selectors of television receiving sets, and to the novel combination of such selectors and wipers.

I will confine my description of the device vto such a specific adaptation, but it is to be understood that this is not to be construed as limitative on my invention or on the broader claims appended hereto.

Channel selectors involve a bank of stationary contacts, and a rotatable drum having a series of contact strips whose contacts are selectively engaged with the stationary contacts by rotation of the drum. These contacts require relatively frequent cleaning, as is well understood in the art, in order to maintain good reception, and the cleaning operation is vexatious and time-consuming, as well as relatively costly. This is particularly true of the stationary contacts, for they are so relatively inaccessible as to require, for usual cleaning purposes, the removal of the tuner from the chassis, and then at least partial disassembly of the tuner. Y

In my copending application entitled Terminal Wiper, iiled under instant date herewith, Serial No. 356,005, there is shown and claimed a wiper adapted to be applied to a housing flange, and to wipe and clean the drum contacts during normal channel-selecting rotation of the drum.

It is the major object of the present invention to provide a cleaning wiper carried by the drum and acting, during normal channel-selecting rotation of the drum, to wipe clean the stationary contacts, thus making separate cleaning operations unnecessary. Without conscious efto obvious advantage.

It is also among the objects of my invention to provide a cleaning wiper which is of extremely simple construction and yet most eiicient in operation. It is a special feature of the invention that the cleaner may be easily and quickly installed without the use of tools, and yet is securely held in place until such time as it is to be purposely removed-whereupon its detachment may be accomplished quickly and easily.

Itis a further object of the invention to provide a novel association of such a cleaner and wiper with the drum of a channel selector.

Other objects and features of the invention will be apparent from the following detailed description, reference being made to the accompanying drawings, in which Fig. 1 is a fragmentary plan view of a tuner or channel selector wherein my improved wiper is incorporated;

Fig. 2 is a section on line 2--2 of Fig. l;

Fig. 3 is an enlarged fragmentary section taken from the position of line 3 3 in Fig. 1;

Fig. 4 is an enlarged fragmentary View of one of the drum iianges when the contact strip and cleaner are absent therefrom;

2,741,683 Patented Apr. 10, 1956 p ICC Fig. 5 is a perspective view of a usual contact strip for the drum;

Fig. 6 is a perspective view of the holderelement of my improved wiper before the wiping pad has been applied thereto;

Fig. 7 is an enlarged end elevation of Fig. 6, as viewed from the position of arrow A;

Fig. 8 is an enlarged end elevation of Fig. 6, as viewed from the position of arrow B;

f Fig. 9 is an enlarged section on line 9-9 of Fig. l.

I have illustrated more or less conventionally some of the essential elements of one type of standard tuner or channel selector 10. Only a fragment of the tuner is Shown, the showing being limited to such parts as are in some way concerned with the cleaning problem and my solution of that problem. Thus, the drum 11 has a shaft 12 which mounts the drum for rotation with respect to housing 13. A bank of stationary, spring terminals 14 is supported on a housing flange 1S and is positioned to be engaged selectively by drum contacts 16 when the drum is rotated, all the terminals of a given row 17 simultaneously engaging contacts 14 when the drum is rotated to a given position by manual operation of shaft 12.

The drum 11 is made up, in part, of a pair of axially spaced lianges 18 and 19 carried on shaft 12, the flange 18 serving as a support for elements to be described and being notched at 20 to receive spring pressed detent 20a whereby the contacts 16 are surely registered and releasably held in engagement with contacts 14 when the drum is rotated to selecta given channel.

The peripheral face of the drum, proper, is' made up of a plurality of non-conductive, transversely arcuate, contact strips 21a, each of these strips carrying a row 17 of contacts 16 which are selectively electrically connected to station selector coils 22 in a well known manner. The row 17 parallels and lies adjacent one edge of strip 21a. One end of the strip 21a is provided with spaced tongues 23a and the other end is provided with a wide central tongue 24a, the tongues 23a being taken within matching apertures 25 in drum flange 18, and tongue 24a being taken between lugs 26 on flange 19. Hooked spring tongues 27, integral with the at spring ring 28 which is riveted to flange 19, spring over the tongues 24a to individually hold the strips releasably in position. It will be seen that by springing back a given tongue 27 a given strip 21a may easily be detached from or attached to the drum flanges.

So much ofthe structure as has been described is standard, each strip 21a representing a given channel or a given channel position. It Will be recognized that if contacts 14 are to be cleaned in the usual manner, the selector 10 must be removed from the television receiver chassis, and then drum 11 must be detached to render said contacts accessible to a cleaning tool. My invention embodies the idea of placing a cleaning wiper or wipers on the drum so that, during normal channel selecting rotation of the drum, the wiper will relatively frequently wipe the contacts clean.

Normally, in any given location there are fewer available channels than there are strips 21a on the drum, so, usually, one or more of said strips are, in electrical effect, dummies. I take advantage of this fact to replace one or more of the dummies with contact wipers. Thus, assuming that the original strip between the two central strips 21a in Fig. l, is a dummy, that dummy strip is detached as has been described, leaving open the corresponding apertures 25 of ange 18, and leaving unoccupied the space between the corresponding lugs 26 on flange 19. Then my improved wiper and cleaner 30 is substituted in place of the detached dummy strip.

Wiper 30 is made up of a holder strip 21 of rigid material, fiber, for instance, having the same length as a istandard `strip 2111, andhavingtongues1.23..,ands24scorresponding, respectively, to tongues 23a and 24a. However, the over-all width of strip 2l is preferably somewhat less itlran""`that`cif astandardstipla. -r`Whileethe strip M may be transversely arcuate to correspond to thefeurvaturefof a standard stripyitfis so-narrowfandrelativly'thinhat it "is feasble i to -make 5 it fflat, vlas shown, in' which event it is n preferable that the undersides of tongues 23and'2'4` becut arcuatelyfas-at 23 and "24,respec'tiv`ely,to -correspond With the curvature of a standardfstrip,andthusbeftalcen lby LA'the l'flanges in r`a manner to prevent tilting or racking of the wiper strip.

Preferablyone edge 'ofstripZl is' providedwithan eloni"gated-'notch' 3l," presenting oppositelyffacingi-shoulders 32 fv'vhicl'iare spaced apartby aidistance'slightlyf greater than 1the vover-all lengthlofi 'the l'bank'- of contacts '5124.

To \strip-21 lapply a'vwiperpadwhich mayfor'imay Lnotf be impregnated witha cleaning substance *such fas Vaseline :While'I may usef-anyj'suitable"V wipin-gr-` material -fsuehf'as feltz or fabric, i'Ihave foun'd' that nylon ffabr'ic" or webbing? particularly ,well serves fthe purpose, v4-as' -it gives a gentle-1scouringl action that performs' the` cleaningf opera- -tion quickly Aand well,v `and yetfdoes not'y 'unduly wear er fabrade the contact surface.

'As"a1preferre'd, vibut not limitative,` meansfor :applying and securing thefpadtotheholdingstrip, Ifimakeithepad iini-the-iformvof-a sleevefencirclin'g the istrip, thefsleeve .beingl entered in notch 31, whereby shoulders "'32: hol'dit T fagainstl longitudinal displacement. To' insure that: at yleast afportion ofthe -sleeve is hel'd outwardly far=fenough^to reffectivelyengage: all `rthe .contacts 1114 when the-"drumI is properly rotated,I'v prefer to4 insert-laf narrow pad ordstrip 34, of somewhat resilient materiaLrbetweenthesleeveland strip -lalongthe edgewhich"corresponds'l'tosthat edge of the standard VstripZawhich?Jliesradjacent to contactzrow -17. The narrowiiillerpad 34. maybefrnadejforkinstance, 'oftfeltland'may be cemented. tovthe'topl of strip 211 lbefore "sleeve' is applied. Conveniently, the1'sleevermay1be formed/.and vsecured in 'position by @wrapping .the nylon webbing' fairly `tightly/'around st'rip'EZl and 4padll'varid "then welding the meeting edgesof Ythe `webbingfbyf'the use offa solvent, such a junction beingindicatediatfSS.

*With the stripZlv and sleever33 a'ssernbledfasfdescibed, itfwill be seen that it takes: but? an instant torretractlspring f.`-hook*27, to insert the wiper't in the :placefof :the removed dummy` strip, and, finally, to'frelease hook27. Theredafter the wiperisreleasablyffbut krmly-"held, to drum 1-1, :fand whenever the -drurn isi-rotated tocarry the Wiper past contacts 14,V the latterwillbe wiped c1eanby1pad33. v-If the selector position occupied by wiper 30 becomes fiactive',L it is 'but-a::moments taskto rshift' the 1 wiper to an finactive position and ireplace it with .an factive strip 21a.

Thus, in the normal practice of rotating drum 11 to select channels, there is an expectancy that contacts 14 will be relatively frequently wiped. The frequency periods between wipings may be reduced by providing a number of angularly spaced wipersonthe,drum, provided, of course, there are Yavailable appropriate dummystrips.

WhileIV have shown and described" apreferred embodiment of my-inventionfvarious .changesindesigm structure and arrangement may be rmade without departing from the spirit and scopeof the appended claims.

I claim:

l. In combination, a channel selector drum embodying axially spaced flanges, a plurality of detachable contact strips extending axially of the drum from flange to flange and each forming an arcuate portionof the'periphery of the drum,'two -of saidstripsbeing angularly'rspacedfapart 'by reason ofthe absence of the normallyfintermediate strip, and a wiperreplacing the absentfstrip, `,and embodying lan elongated, substantially iiat'and rigid 'plateextend- -ingaXially of' the drum-from flange to'ange-andjdetachably end-connected to said lianges, and 'a` wiperjpadaplplied* to* theouter-face of'said `plate andr extending' longi- 'tudinally"`thereof, the -outer'face Aof the plate'being substan'tially'ush with the-outer faces of'theadjacent strips.

2. A terminal wiperembodying 'an elongated,'substan ftially flat and rigid plateya centraltongue extending from one end ofthe plate and whose under Aface is'cut-arcuately, :a pair of spacedtongues-extendingfrom the'otherend-of the plate, theunder'faces of the tongues'being cut'arcua-tely with-'the same curvaturefas that-of the-central tongue, ,and Ya ywiper pad applied tothe upper face gof the plate VAandfflongitudlnal'ly stopping short efsaid tongues.

-f3.- A terminal Wipern embodying an elongated, lsubstantially atf-and'rigid plate, a central-tongueextending-from oneendfof the plate and whose 'under face is cut arcuately, =a -pairv of spaced -tongues extendingy from the otherendrof the plate, the under faces of the tonguesbeingf-cutarcu- "ately with the sameV curvature as that of the-central tongue, there being a notchcut in onel sideedge -of"the`plate,and v.ia l sleeve of wiping ymaterial extending lon'gitudinally `of .andaround the Vplateand through thenotch.

AReferences Cited inthe leA of thispatent 'UNITED STATES PATENTS VGreat Britain *Junel 3,1 1'912 auf, 

